The ends of a band-like body such as the collar for animals, the bag belt or the like are often coupled to each other via a buckle. Such buckle is generally configured of a detachable inserting body attached to one end of a belt and a coupling tool body that is attached to the other end of the belt and inserts the detachable inserting body thereinto, which can engage with each other.
For example, Patent document 1 (Unexamined Patent Publication No. 2003-102516, JP2003-102516A) proposes a coupling tool that attempts to obtain adequate strength while achieving reduction in size and weight. In the coupling tool in Patent document 1, a pair of hook-like protruding engaging claws are integrally formed on both respective sides of a detachable inserting body, while a coupling tool body is configured of upper and lower plates that have a storage part therebetween, a pair of engaging parts supported in the storage part so as to freely swing about respective spindles, and a spring member that biases engaging claws of the pair of engaging parts to get closer to each other. The engaging claws of the detachable inserting body engage with the engaging claws of the coupling tool body.
However, in the coupling tool in Patent document 1, in order to satisfy necessary strength, components of the detachable inserting body and the coupling tool body each are made of metal. Thus, the tool achieves adequate strength, but has a complicated structure including a lot of components, and is made of metal as a whole as mentioned above. As a result, the tool is considerably heavy.
Then, in order to provide an inexpensive and light-weighted buckle that includes a small number of components while achieving necessary and adequate strength, Inventors of Patent document 2 (Unexamined Patent Publication No. 2010-110502, JP2010-110502A) propose a buckle that couples a band-like body by inserting an inserting piece protrudingly provided on a male member into an insertion port of a female member.
More specifically, in the buckle in Patent document 2, the inserting piece of the male member includes a pair of engaged parts, and the female member is formed of one metal wire and includes a pair of arms that are bent and protruded from both respective ends of a base. The pair of arms are provided with a pair of respective engaging parts, integrally formed by bending, and the engaging parts can be engaged/disengaged with the engaged parts of the inserting piece as a distance between the arms are widened/narrowed due to elastic deformation.